The diffusion of As was studied at 1000C in relaxed Si0.9Ge0.1 structures grown using molecular beam epitaxy. The intrinsic diffusivity of As in Si0.9Ge0.1 was shown to be enhanced, over Si, by a factor of 2; in agreement with the literature. Using selective point defect injection, obtained by surface reactions during using rapid thermal annealing in an O atmosphere, clear evidence of the participation of both vacancy and interstitial defects in the diffusion of As in Si0.9Ge0.1 was obtained. A qualitatively higher contribution of vacancies in Si0.9Ge0.1, than in Si, was apparent.

Evidence for a Vacancy and Interstitial Mediated Diffusion of As in Si and Si0.9Ge0.1. S.Uppal, A.F.W.Willoughby, J.M.Bonar, J.Zhang: Applied Physics Letters, 2004, 85[4], 552-4

Figure 15

Diffusivity of As in Si0.8Ge0.2

(Open squares: As in SiGe; filled squares: As in Si)